The battery life (that is, the time span during which a battery can be used before the battery charge is depleted) of a battery-powered mobile terminal is a very important factor in the user experience of such a terminal. A shorter than expected battery life can be very unsatisfactory and can harm the user's satisfaction, in spite of any appealing features of the terminal such as colour screen, camera and browsing services. Examples of battery-powered mobile terminals are a mobile phone, a barcode scanner, a remote control unit and a personal digital assistant (PDA).
The battery life of a battery-powered terminal is dependent on the way a user uses the battery-powered terminal (which user activities are carried out, for how long). A different (battery-powered) terminal usage will cause different time durations before a terminal shuts down due to low battery. As a consequence battery-powered terminals will differ in their relative battery performance for typical groups of users. In order to relate power off time to a typical group of users, usage profiles can be used.
In order for a battery-powered operator/terminal vendor to provide the end user with a terminal that has a satisfactory battery life, exhaustive measuring and testing of the battery-powered terminal is necessary. This includes the ‘classic’ (standardized) testing of talk-time and standby-time (these values are often used by terminal vendors/operators when selling their battery-powered terminals). During such tests the terminal is used according to a usage profile until the battery charge is depleted, whereby the usage profile comprises a plurality of user activities, like performing a voice call, to be performed by a user.
Nowadays these tests are not satisfactory because of the extended functionality of battery-powered terminals. Users can perform a large number of other user activities on their battery-powered terminal, such as browsing, running java applications, camera use, etc. It is a problem that there is no standardized method of measuring the power consumption of these activities. This makes it difficult to benchmark the battery life of battery-powered terminals, in particular to benchmark per usage profile, where each usage profile comprises a number of user activities.
The Prior Art fails to provide a satisfactory solution. U.S. Pat. No. 6,957,091 discloses a portable multi-band communication device containing a power amplifier, a battery and a controller which controls the output power level of the communication device. The controller monitors the digital output signal and in response determines the consumption of electrical energy from the battery. A control value of the output power amplifier is used for power consumption estimation. Clearly, U.S. Pat. No. 6,957,091 fails to take the power consumption effects of various distinct user activities into account.
United States Patent Application US 2004/098222 discloses a method of determining usage time for a plurality of modes of a mobile device. Storage locations are provided for storing current usage values, each storage location being associated with a particular mode of the terminal. Thus various modes may be taken into account, but the individual power consumption of different user activities, and the causes of those differences, are not addressed, thus necessarily causing inaccurate estimates when the power consumption due to various user activities has to be predicted.